Both higher CSF p‐NfH and NfL levels were significantly associated with fast‐progressing ALS (OR 1.834, 95% CI 1.246‐3.203, P = .008, and OR 1.006, 95% CI 1.002‐1.015, P = .033, respectively). This evidence concerns the gene NEFH and amyotrophic lateral sclerosis.